| Section
303(d) of the 1972 Clean Water Act (CWA) requires all states
to develop a list of their state’s impaired waterbodies. The
303(d) list of impaired waterbodies consists of those waterbodies
that do not meet state regulatory water quality standards even
with the current pollution controls in place (even after point
sources of pollution have installed the minimum levels of pollution
controls). The CWA also requires all states to establish priority
rankings for waters on the 303(d) list and develop Total Maximum
Daily Loads (TMDLs) for these waters based on their individual
priority ranking. A
TMDL is a pollution budget for a specific waterbody (river,
lake, stream, etc.). It is the maximum amount of a pollutant
(sum of allowable pollutant loads from point and nonpoint
sources) that can be released into a waterbody without causing
the waterbody to become impaired and/or violate state water
quality standards. A TMDL also must include a margin of safety
to allow for any uncertainties in the scientific methods used
to derive the TMDL (water quality modeling assumptions, etc.) |
|
TMDL= |
Wasteload
Allocation (point sources)
+
Load Allocation (nonpoint sources and natural background
sources
+
Margin of Safety |
TMDL
(Total Maximum Daily Load) Facts
Louisiana TMDL List
303(d)
305(d)
|
